Recently, the use of cameras including solid-state imaging devices such as charge coupled devices (CCDs) or complementary metal oxide semiconductor (CMOS) image sensors has greatly increased (hereinafter, cameras including solid-state imaging devices will be simply referred to as cameras).
Also, the degree of pixel integration in solid-state imaging devices has been increased to improve the resolution of cameras. Along with this, small and lightweight cameras have been developed by improving the performance of lens optical systems included in the cameras.
In general, a lens optical system of a small camera (e.g., a cellular phone camera) includes many lenses including at least one glass lens for providing a certain degree of performance. However, the manufacturing costs of glass lenses are high, and it is difficult to manufacture a small lens optical system using glass lenses because of limitations in forming/machining processes of the glass lenses. Also, existing lens optical systems used in camera phones generally have an angle of view within a range of about 60° to about 65°.
There is a need for a lens optical system having high performance/high resolution, a relatively wide angle of view, and a small size and light weight as well as features for solving the problems of the glass lenses.